Some variables can't be defined in PACKER_VARIABLE_FILE

[sidewinder12s]

I think #1079 missed a couple more variables that override what is in the Packer variables files:

https://github.com/awslabs/amazon-eks-ami/blob/master/Makefile#L9-L10

I had to remove that before I could build the AMI in us-east-1. Otherwise my AWS_DEFAULT_REGION variable overrode the binary_bucket_region variable that is explicitly set to us-west-2.

[cartermckinnon]

Do you mean you're trying to set aws_region and binary_bucket_region in a user-provided variable file (PACKER_VARIABLE_FILE)?

[sidewinder12s]

I updated aws_region to us-east-1 in a user provided variable file & I have AWS_DEFAULT_REGION set to us-east-1 in my environment.

The makefile will override those region variables depending on if AWS_DEFAULT_REGION is set. My read of some of the PRs that have added the packer variable file was that it will be the preferred configuration method and you probably want to make the makefile do less right?

[cartermckinnon]

Makes sense; I was just trying to figure out if we changed existing behavior unintentionally. It'd be great to remove this limitation and allow all template variables to be defined in the user-provided variable file; if you have an idea, feel free to open a PR. 😄

it will be the preferred configuration method

Time will tell; I primarily made this change because it made some things easier in our internal build process. But yeah I think many users could benefit from it.

and you probably want to make the makefile do less right?

Not necessarily; I think the logic around aws_region, instance_type, etc. is handy. But the user's input should take precedence, obviously.